Wire joint, especially for electrical shot-firing outfits or similar provisional electrical circuits



May 30, 1939. w NQRRES 2,160,313

WIRE JOINT, ESPECIALLY FOR ELECTRICAL SHOT-FIRING OUTFITS 0R SIMILARPROVISIONAL ELECTRICAL CIRCUITS Filed March 6, 1937 d H 7191] 7 F119. 2fi I ONDUCT/IVG L/A/l/YG cououcrma Imma- CONDUC TING L/N //1 veal-or:wa, N0 RRE S Patented May 30,, 1939 PATENT OFFICE WIRE JOINT, ESPECIALLYFOR ELECTRICAL SHOT-FIRING OUTFITS OR SIMILAR PRO- VISIONAL ELECTRICALCIRCUITS Wilhelm Nor-res, Dorsten, Germany Application March 6, 1937,Serial No. 129,331 In'Germany March 12, 1936 3 Claims.

This invention relates to wire-joints and more especially. towire-joints to be used with advantage in electrical shot-firing outfitsor similar provisional electrical circuits and the like.

In electrical shot-firing outfits, especially when used below ground, acareful mounting of the fil four requirements.

. outfit and especially of the ignition-circuit thereof is ofconsiderable importance. In outfits of this kind frequently a greaternumber of shots has to be fired simultaneously and in consequencethereof an appropriate number of connections and wire-joints will benecessary. Each of these connections or wire-joints, moreover, has toful- In the first place there must be a good contact in the wire-jointto avoid an undue resistance at the contact points and unfavorableconditions resulting therefrom with regard to the total resistance ofthe ignition circuit including the shot-firing fuses forming part of theoutfit. Furthermore, the wire-joints must be of sufiicient mechanicalstrength to prevent separation of the wires by a pull which mayoccasionally be exerted thereunto. Also, the wires connected by thejoint must be completely insulated towards the outside, as otherwise ashunt to said wires may eventually arise or some current source otherthan that of the ignition circuit may act on said fuses. Finally, theconnection between the wires should permit of being made in a simplemanner and within the shortest possible time. Moreover, the wire-jointat the same time must comply with all four of these requirements, ofwhich the last-mentioned is most essential, especially in shot-firingoutfits working below ground.

By my invention all of the aforesaid requirements are fully andsuccessfully complied with. According to my invention the wire-jointsfor shot-firing outfits or similar provisional electrical circuits aremade by inserting the bare ends of the wires to be connected with eachother into an insulating bushing closed at one end thereof and providedwith an interior lining of conducting material, and thereupon saidbushing together with said lining and the bare end of the wires insertedthereinto is sharply bentto provide a firm and reliable joint to beeasily and conveniently made by hand without the use of any implement,such as pliers. Moreover, as the bare ends of the wires to be connectedwith eachother are inserted into the lining of the bushing as far as tothe bottom thereof, eventually also some part of the insulating coveringof the wires may thus enter said lining or bushing. In spite of this thebare ends of the wires will be safely secured in position, and a goodinsulation of the joint as a whole may readily be attained withcertainty according to my invention by sharply bending said bushingtogether with said lining and the ends of the wires therein. In thismanner there will also be attained a good electrical joint between thetwo wires on account of said conducting lining. 'In addition to this,the wire-joint will be of great mechanical strength and especially ableto withstand tensile strains imposed thereon. The wires may immediatelyagain be disconnected by straightening out said bushing, the bare Wireends now being in condition. ready for making some other connection, forinstance, by inserting the same into another wire-joint.

It is well known in electrical work to connect two conductors or wireswith eachother by inserting the same in opposite directionsintoasmallmetal tube insulated at the outside and to twist this tube with thewires therein by means of a suitable implement, such as pliers or bybending said tube and wires into wave-shape. A wire-joint of this kind,however, is rather destined for making permanent connections and,therefore, not suitable for the quick making of ignition-circuits forshot-firing outfits to be laid provisionally below ground. The reasonfor this consists therein that this known joint or connection must bemade very carefully and consequently requires a considerable amount oftime. Moreover, when using this known joint, there will be thepossibility that the two wires inserted into the tube may project at oneor both bare ends out of the tube with the result, that the joint willbe not insulated at the projecting end or ends of the wires. The use ofa tool for making the joint, moreover, is inconvenient and in additionto this, the tool may easily be lost, especially when working belowground. On the other hand, by connecting the wires by means of theaforementioned bushing closed at one end thereof, in accordance withthis invention and by sharply bending said bushing the so obtainedwire-joint is in every respect superior to known joints and at the sametime of greater simplicity with regard to making and breaking theconnection. Moreover, the joint which forms part of my invention isespecially suitable for work below ground. In order to lay ignitioncircuits for shot-firing outfits at very wet places, for instance, whenblasting in water, the insulating effect of the wire-joint may befurther increased by using the aforedescribed bushings with a filling ofsoft or plastical insulating material consisting, for instance, of atar-like mass, Vaseline, or the like.

A filling of this kind, moreover, does not run out of the bushing eitherduring handling or during transport. When inserting the ends of thewires to be connected with eachother into said bushing and sharplybending the latter, said filling will protrude from the orifice of saidbushing and this will safely prevent access of water to the bare ends ofthe wires in the joint, even if the joint is for some longer time keptin water.

During sharply bending the bushing with the ends of thewires therein,said filling of insulating material will be forced out of said bushing,while at the same time the bare ends of the wires will be pressedagainst eachother and against said 5 conducting lining to provide anintimate contact between the wires, the filling material preventing inno way a good electrical joint between the wires. A

In the accompanying drawing, I have shown some examples of constructionof my novel wirejoint, Figs, 1 and 2 being a longitudinal section of theaforesaid bushing and lining in straight condition, Figs. 3 and 4showing said bushing and lining together with the wire-ends therein incompleted, that is bent, condition of the joint,

and Fig. 5 a diagram showing an electrical shotfiring outfit includingwire-joints according to my invention.

As shown in Fig. 1 my novel wire-joint consists 0 of a bushing a ofinsulating material, said bushing being closed at one end thereof andcomprising a tube or lining b of conduction material provided in theinterior of said bushing a, the end a of the insulating bushingprojecting be- 5 yond said tube or lining b. In order to make the jointthe bare ends ofv the wires 0 and d to be connected with each other areinserted together with'the ends of their insulating covering into saidtube or lining b and thereupon said 0 bushing a, together with saidlining b and the ends of the wires c and d therein, is sharply bent inthe manner indicated in Fig. 3.

i The insulating material used for the bushing a is a material which maybe bent into a different shape and then holds its shape, and such that 5bushing 0. together with the lining b and the wires 0 and d therein islikewise sharply bent to produce a conducting and strong connectionbetween the two wires 0 and d. In the present case, the ends of the twowires are also firmly surrounded by the conducting lining b, thussecuring a good electrical joint even in case the bare ends of the wiresare not in full and immediate con- ,tact with each other. Moreover, thisform of joint is likewise suitable to resist against a pull 5 exertedonto the two wires interrupting the connection and even in case of astrong pull connection will be maintained in contradistinction to theaforementioned wire-joint made by twisting. The construction of thewire-joint shown' in Fig. 2,

7 according to which one wire is fixedly connected to the. conductinglining b, is possessed of the further advantage, that the shot-firingfuse connected to the wires 0 and a may be protected during installingthe outfit against being acted 75 upon by a current source by havingalso the bare end of the wire 0 inserted into the bushing a. In themanner indicated, there may also be attained a good and firm electricaljoint between wires of different diameters by winding the bare ends ofthe wire of smaller diameter around the bare end of the wire of largerdiameter and thereupon inserting both wire ends into the bushing andsharply bending the same as indicated in Fig. 4. I

In Fig. 6 I have shown an electrical shotfiring outfit comprisingseveral fuses placed in the ground and connected in series with eachother by means of wires and wire-joints a}, a a and a. The circuitincluding said fuses in series is connected to the ignition wires e andf eventually with insertion of a surplus of wire g. From the foregoingexplanations and especially from Fig. 5 of the drawing it may be seenthat wire-joints constructed according to my present invention are ofgreat importance in connection with provisionally installedignitioncircuits forming part of shot-firing outfits, said wire-jointsmaking it possible to establish a good, well-insulated and mechanicallystrong electrical joint between wires without the use of any, tool. Afurther advantage consists therein that the wire-joints made ,at theends of the ignitioncircuit or at the ends of said surplus of wire g mayconveniently'be disconnected, at the same time retaining the barewire-ends in condition to be used for making further connections.Disconnection of the wires may solely be attained by straightening outthe bent bushing a and withdrawing therefrom the ends of the wires,which may likewise be done without the use of any tool.

I claim:

1. A wire joint for connecting wires of electrical ignition circuits forshot-firing outfits or similar provisional electrical circuita'saidjoint comprising a tubular shaped bushing of insulating material, a pairof insulated wires having their ends free of insulation and exposed,engaging the open end of the bushing, only the insulated. parts of thewires protruding from the bushing, and a conducting lining interiorly ofsaid bushing and contacting with said exposed uninsulated ends of saidwires, said bushing together with said conducting lining being sharplybent, with the ends of the bushing adjacent each other, to remain in theposition to which the bushing was bent.

2. A wire joint for connecting wires of electrical ignition circuits forshot-firing outfits or end, a pair of insulated wires having their endsfree of insulation and exposed, engaging the open end of the bushing sothat only the insulated parts of the wires protrude from the bushing,and a conducting lining interiorly of said bushingand contacting withsaid exposed uninsulated ends of said wires, one of the wires beingfixedly connected with said conducting lining, and the other wireinserted thereinto, said bushing together with said conducting liningand said other wire therein being sharply bent, with the two ends of thebushing adjacent each other, to remain in the position to which thebushing was bent.

3. A wire joint for connecting wires of electrical ignition circuits forshot-firing outfits or similar provisional electrical circuits, saidjoint comprising a bushin g\ of insulating material closed at one endthereof and open at the other end, a pair of insulatedwires having theirends conducting lining being sharply bent so that the two ends of thebushing are adjacent each othef and remain in the position in which thebushing was bent, and a plastical insulating material filling saidbushing to prevent conducting materials from entering the bushing andcontacting 5 with the exposed ends of the wires.

WILHELM NORRES

